Circuit breaker



Patented June 30, 1942 CIRCUIT BBEAKER Hiller D. Dorfman, Forest Hills, and Gerald J. Freese, East McKeesport, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,

Pennsylvania.

a corporation of Application August 22, 1941, Serial No. 407,884

19 Claims.

The invention relates to circuit breakers oi the trip free type having an operating mechanism which is manually operable to open and close the breaker contacts, and which is automatcally tripped to cause opening of the com tacts in response to predetermined abnormal conditions in the circuit.

Circuit breakers when installed in certain locations, are subjected to very severe jars and shocks which are often of such magnitude as to cause false opening or tripping of the circuit breakers in the vicinity, thus disrupting the electrical service when it is very essential. Under emergency conditlns,'it is desirable that the circuit breaker shall remain closed even though there be overloads on the circuit which would ordinarily open the breaker. In some cases, the shocks may be so severe as to cause the circuit breaker operating handle or other parts connected to the contacts to move to open position thereby falsely opening the breaker in this manner.

it has been proposed to use non-trip free cir cuit breakers, and station an individual at each such breaker during an. emergency to hold it closed. lll'his is not satisfactory, however, because the very important and desired 'advantages oi the modern trip free circuit breakers are lost under normal conditions. it has also been proposed to provide the circuit breaker with a man ually operable locking member adapted to be moved to and manually held in locking position to lock the circuit breaker latch or trip bar against tripping movement. This latter proposal is not a satisfactory solution for twolmportant reasons, the first being that it requires a man to be stationed at each individual breaker, and the second being that the locking of the breaker latch or trip bar is not alone sufficient to prevent false opening of the breaker in the case of severe shocks which will move the operating handie or other part connected to the contacts to open position thereby opening the breaker even. if the latch is locked.

An object of the invention a trip free circuit breaker proved construction whereby prevent opening thereof by jars circuit conditions.

Another object of the invention is the provision of a trip free circuit breaker embodying an improved locking device manually settable to locking position to lock the circuit breaker in closed position to prevent opening thereof by is the provision of embody an imit can be locked to or by abnormal of the circuit breaker overloads, jars or any means as long as the locking device is in locking position.

Another object of the invention is the provision of a trip free circuit breaker embodying a locking device which can be manually set to locking position to prevent opening of the circuit breaker by forces acting to release the mechanism latch and also by forces acting to move the operating handle or other parts connected to the contacts to open position.

Another object of the invention is the provision of a trip free circuit breaker embodying a single locking element which is manually settable to a locking position in which it prevents release movement of the circuit breaker latch and also prevents opening movement of. the breaker operating member or other parts connected to the contacts.

Another object of the invention is the provision of an improved locking device for trip free circuit breakers, which is simple, reliable and inexpensive to manufacture, andwhich can be. applied to many existing circuit breakers without substantial alteration of the breakers.

The novel features that are considered characteristic of the invention are set forth in par'- ticular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof the following detailed description of one embodiment thereof when read in conjunction with the accompanying drawings, in which: v

Figure 1 is a vertical sectional view of a multipole circuit breaker embodying the features of the invention, the breaker being shown in the closed position with the locking device set in locking position,

Fig. 2 is a fragmentary sectional view of the circuit breaker showing the locking device in non-locking position,

Fig. 3 is a fragmentary horizontal sectional view taken substantially on the line DIL-HI of Fig. 1 toV illustrate features of construction of the locking device,

Fig. 4 is a fragmentary front elevational view showing the lower portion of the circuit breaker and the operating knob of the locking device,

Fig. 5 is a fragmentary sectional view of the circuit breaker taken substantially along the line V-V of Fig. 1, and

Fig. 6 is an exploded view of the locking device.

Referring to the drawings, particularly Figs. 1

will be best understood from and 5 thereof, the three-pole circuit breaker illustrated comprises a base 9 of molded insulating material having mounted thereon six terminals I I, two for each of the three poles of the breaker, three stationary contacts i3, an arc extinguishing device I5 for each of the three poles, the circuit breaker operating mechanism I1 which has associated therewith the three movable switch members I9, andthe trip device indicated generally at 2l. A separate cover 23 alsofofmmolded insulating material is provided for cooperating with the base 9 to form an enclosing casing for the circuit breaker. The base 9 and cover 23 are secured together by four bolts 21 (Figs. 4 and 5, only *wo being shown) which extend .through bolt holes located in thel cover adjacent the'four corners thereof and engage threaded nuts` (not shown) embedded in the base 9. The base 9 and cover 23 are each provided with longitudinally extending partitions 29 (Fig. 5) formed iintegral therewith, which are aligned when the cover is on the base. These partitions serve to separate and insulate the three poles of the breaker from each other.

Each of the switch members I9 includes a resilient switch arm 3I preferably of spring steel secured at one end to the switch member I9 and which supports a movable contact 33 at the other end, each movable contact 33 being adapted to cooperate with a corresponding one of the stationary contacts.

A flexible shunt conductor 35 is provided for connecting each of the movable contacts 33 with a corresponding one of the conducting members 31 which serve to complete the circuit from the shunts 35 to the trip device 2I. Each conducting member 31 is secured at its upper end to the base 9 by means of a screw 39, this screw also serving to fasten the lower terminal of the shunt 35 to the conducting member 31.

The three-switch member frames I9 which are substantially channel-shaped adjacent their lower ends are rigidly connected together by means of. an insulating tie-bar 4I which extends through suitable openings provided therefor in the channel-shaped yportions of the switch members I9, the tie-bar ybeing rigidly fastened to each switch member, The three switch members are thus mechanically connected for simultaneous movement together but insulated from one another, by the insulating tie-bar 4 I.

Each stationary contact I3 is secured to the lower end of a corresponding terminal strip 43 which is, in turn, secured to the base by a screw 45. Each terminal strip 43 is suitably secured at its upper end to a corresponding one of the upper terminals II. Both the upper and lower terminals I I of the circuit breaker are embedded or molded in openings provided therefor in the base 9 and each has a passage therethrough for receiving a terminal screw, or a terminal stud of a switchboard. An arc runner 41 of arc resisting conducting material is secured to ea-ch terminal strip 43 adjacent the stationary contact I3, by means of the Ifastening screw 45.

The arc extinguishers I5 may be of any suitable type but are preferably of the space plate type and each comprises a stack of slotted plates of magnetic lmaterial which are insulated from each other and positioned adjacent the path of movement of the correspondingmovable contact. The slotted plates are supported in spaced relation with each other in a stack by means of a U-shaped member 49 of insulating material disposed about the plates.

Ameans, one for each pole of the breaker.

Three terminal strips 5I are provided for connecting the lower circuit breaker terminals II to the corresponding poles of the trip device 2|, the lower end of the terminals 5I being secured to the terminals II. Each conducting member 31 comprises a formed strip of conducting material which is shaped as shown in Fig. 1 and serves as the energizing Winding of one of the electromagnetic tripping means of the trip device 2l, there being three such electromagnetic tripping The upper angularly bent end of the conducting member 31 is fastened to the base by the screw 39 as previously described. Each conducting member 31 passes through a slot provided thereforin an insulating plate 53 and is looped over one leg of the corresponding magnet core I I1 of the trip device, and the lower end of the conducting member is bent angularly and secured to the lower terminal strip 5I by a screw 55. The screw 55 also serves to secure the terminal strip 5I to the circuit breaker base 9.

The electrical circuit for each of the poles is essentially the same. Beginning with the lower terminal I I the current ilows successively through the terminal strip 5I, the conducting member 31, flexible shunt conductor 3 5, the movable contact member 33, the stationary contact I3, and thence through the upper terminal strip 43 to the upper terminal II.

The operating mechanism I1 which is of the -snap action type is supported on a U-shaped metal frame 59 and comprises a bifurcated operating lever 6I, two pivotally connected toggle links 63 and 65 forming a toggle which is connected to the center pole switch member I9, two pairs of overcenter springs 61vfor operatively connecting the operating lever 6I with the knee pivot lpin 69 of the toggle, and the releasable lever 1I for supporting the outer end of the toggle so as to provide a means whereby actuation v of the trip device 2I can cause the mechanism to automatically move all of the switch members I9 to open circuit position. The bifurcated operating lever 6I straddles the sides of the frame 59 and is pivotally supported on the sides of the frame by. means of two pivot pins 13 (only one being shown) An operating handle 15 of molded insulating material is secured to the outer end of the oper-ating lever 6| and extends through an velongated slot 11 in the circuit breaker cover 23 to provide for manual operation of the circuit breaker. The operating handle 15 is provided with an arcuate shield 19 formed integral thereof the operating handle.

The mechanically connected switch members I9 are pivotally supported on the U-shaped main frame 59 by means-of a pivot pin 8I which engages the channel-shaped portion of the central switch member I9. One end of the inner toggle link 65 is likewise pivoted to the center pole switch member I9 through thev agency of a pivot pin 83 which provides the only mechanical connection between the operating mechanism and the three switch members. The knee pivot pin 69 of the operating toggle extends for some distanceon either side of the joined toggle links and each of the projecting portions is pivotally connected to the inner ends of a pair of the overcenter'springs 61 by a spring support 85. The two pairs of overcenter springs 61 lie on opposite sides of the toggle link 63 and releasable lever 1 I, and the outer ends of the springs are fastened i threads into an opening to the cross portion of the bifurcated operating lever 6|. The outer end of the toggle link 63 is pivotally connected to the releasable lever 1| by a pin 81, and this releasable lever is in turn pivotally supported on the U-shaped frame 59 by means of a pivot pin 89. The U-shaped frame 59 is secured to the central portionof the base 9 by a plurality of screws 90.

The trip device 2| includes a rotatably supported trip bar 9| of molded insulating material which has a centrally disposed shaft molded therein by means of which the trip bar is rotatably supported on a pair of brackets 93. The brackets 93 are secured at their inner ends against the opposite side walls of the base 9 and are provided with bearing openings for en-gaging the ends of the shaft of the trip bar 9|. The trip bar is provided with three spaced projections 95 formed integral therewith, one for each pole of the breaker and is also provided with a means for engaging the circuit breaker operating mechanism. This engaging means comprises a pair of substantially parallel plates 91 which are rigidly aixed to the trip bar, a pin 99 which connects the two plates 91 and provides a means for resetting the trip device, and a latch member joining the vouter ends of the plates 91 which latch member is adapted to engage the lower end of the releasable lever 1| and restrain this lever when the trip device is in the untripped position. The brackets 93 which support the trip bar are provided with extensions |03 which are connected at their ends by an insulating rod |05.

Three biiurcated trip members |01 are rotatably mounted in slots provided therefor on the trip bar 9| and each of these tripping members is biased in a clockwise direction.' as viewed in Fig. 1, to tripping position by a pair of springs |09 connected at one end to extensions of the trip member and connected at the other end to the insulating rod |05. Each tripping member |01 is provided with a latch portion ||3 joining the bifurcated ends of the trip member and this latch portion is adapted tobe normally engaged by a latch ||5'on the armature of a corresponding one of the electromagnetic tripping means. Thus each trip member is normally restrained in non-tripping position by the latch of 'its corresponding electromagnetic tripping means.

Each of the electromagnetic tripping means of the trip device includes the U-shaped core ||1 of magnetic material which is mounted by means of a screw ||9 on a cross piece |2| of a supporting frame |23 which is of non-magnetic material, preferably brass. Each supporting frame |23 is secured to the base by means of a screw |25 which passes through the base and provided in a portion of the frame |23.. The frame |23 hasspaced I sides between which the U-shaped magnet core is mounted, and a movable armature |21 is pivotally mounted intermediate its ends at |29 on the frame |23 between 4the side walls thereof.

The armature |21 of each electromagnetic tripping means is biased to a normal unattracted position, as shown in 1, by means of a compression spring v|3| which is interposed between the outer end of the armature lever and an ady justing screw |33 which threads into a cross piece |35 joining the sides of the frame |23. The adjusting screw |33 carries a pin |31 which engages in a notch -in the outwardly extending end, of the armature |21. The adjusting screw |33 thus provides a. means for adjustingthe force of the spring |3| of the electromagnetic tripping means to thereby adjust the value of overload current at which tripping will occur.

As has previously been explained, each conducting member 31 serves as an energizing winding for one of the electromagnetic tripping means and for this purpose each conductor member 31 has a portion which is-looped over the inner leg of its corresponding magnet core ||1, hence each electromagnet is responsive to the current flowing through the corresponding pole or circuit breaker. The trip bar 9| is biased counterclockwise to latching or non-tripping position by three light compression springs |36 each disposed between one of the magnet cores ||1 and a corresponding one of the projections 9'5 of the trip bar. The combined strength of the three springs |36 is considerably less than that of the two trip member springs |09 for any one pole.

When the current flowing through any pol of the breaker is below the magnitude for which its` corresponding electromagnetic tripping means is set to operate, the magnetic force developed thereby is insuicient to move the armature |21 to attracted 'position and consequently the electromagnetic trip means will not operate to trip the breaker. However, as soon as the value of overload current in any pole exceeds that for which the device is set, the magnetic force is then sufficient to move the armature |21 to attracted position against the force of the spring |3| and thereby effect release of the spring biased tripping member |01 of the corresponding pole. When any one of the tripping members |01 is thus released, it is moved to tripping position by the springs |09 and engages the corresponding projection of the trip bar .and moves the trip bar in a clockwisedirection. This movement of the trip bar causes the latch member |0| to release the releasable lever 1| of the circuit breaker mechanism thereby causing automatic opening ofthe contacts of the circuit breaker. Clockwise movement of each trip member |01 when released is limited by a projection |4| carried thereby striking the outer end of the armature lever |21. It will thus be seen that when an overload above a predetermined value occurs in the circuit of any one of the poles of the circuit breaker, it will result in operation of the corre- 4spending electromagnetic tripping means of that pole and cause rotation of the trip bar to trip the circuit breaker operating mechanism and thereby cause opening'of' all of the contacts of the circuit breaker.

The operation of the circuit breaker as thus far described is briefly as follows: The circuit breaker is shown in Fig. 1 in the closed circuit position, the trip device 2| being in the untripped position. Assuming the locking device is in nonlocking position: To open the contacts manually, the operating handle 15 is moved in a clockwise direction, as viewed in Fig. 1, about its pivot 13. This movement moves the line of action of the operating springs 61 below the center of the pivot pin 81 which connects the outer toggle link to the releasablelever and in so doing produces a component of rorce which tends to move the knee pivot pin of the toggle away from the overcenter or closed circuit position toward the collapsed position. Shortly before the operating handle 15 reaches the full open position, this component becomes great enough to set the mechanism in motion and cause collapse of the operating toggle.

The collapse or the toggle causes the switch members I9 to be rotated in a clockwise direction about the common pivot axis 8| to open circuit position.

To close the contacts manually, the operating handle is mov'ed from the open vcircuit position upwardly or in a counterclockwise direction toward the closed position. After the line of action of the overcenter spring 61 crosses the center line of the outer toggle link 63, that link is caused to move toward the overcenter or closed circuit position, thereby causing the three `movable switch members |9 to be operated to the closed circuit position. The closing operation takes place as does the opening operation with a snap action shortly before the operating handle reaches its end position.

When the circuit breaker is in closed circuit position, the releasable lever 1| is biased in a counterclockwise direction, as viewed in Fig. 1,

' about its p ivot 89 by the reaction forces of the springs 61 and is restrained in the normal position shown by the latch member on the trip bar 9|. Upon the occurrence of an overload in the circuit of any pole of the breaker which is of suilicient magnitude to cause operation of the corresponding electromagnetic tripping means, the armature of that tripping means is moved to attracted position thereby releasingthe corresponding spring biased tripping member |01 which thereupon operates to rotate the trip bar 9| in a clockwise direction. This movement of the trip bar eiects release of the lever 1| and the subsequent rotation of the lever 1| causes the pivot 81 to be shifted above the line of action of the overcenter springs 61 thereby resulting in collapse of the toggle and opening of the contacts regardless of the position of the operating handle 15, that is, even though the operating handle may be held in closed position. The breaker is, therefore, entirely trip free. Following each opening operation of the circuit breaker as a result of the operation of the trip device 2 I, it is necessary to restore the operating mechanism and the trip device 2| to an operative condition. This is done by rotating the operating handle in a clockwise direction to the open position. This movement of the operating handle 15 is transmitted to the releasable lever 1| through the engagement of the project` ing member |45 of the operating lever 6| with a portion |41 of the releasable lever 1|. As the releasable lever 1| is thus rotated, by the handle 15, the end thereof engages the pin 99 which forms a part of the mechanism engaging` means and since that pin is rigidly connected to the i trip bar 9|, causes the trip bar to rotate in a counterclockwise direction a suilicient distance to permit the latch member |0| to re-'engage the end of the releasable lever 1|. This re-engagement occurs somewhat before the operating handle 15 reaches the limit of its motion in an opening direction. The resetting movement of the trip bar 9| not only affects the re-engagement of the operating mechanism l1 and the ltrip device 2|, but, in addition, causes a resetting of any or all of the trip members |01 to their latched position, shown in Fig. 1. This is accomplished by the engagement of the projections 95 of'the trip bar with the underside of the tripping members |01. The resetting of the trip members |01 and the re-engaging of the operating mechanism by the latch of the trip device restores the circuit breaker to an operative condition in the open circuit position.v The -contacts may then be manually moved to the closed circuit position exactly as described above.

In order to lock the circuit breaker in closed circuit position and prevent opening thereof either by an overload or severe jars, there is provided in accordance with the invention a locking means indicated generally at I5|. -This locking means comprises a locking element or lever |53 which is pivotally mounted on a bracket |55 carried by the cover 23 of the circuit breaker. 'I'he bracket |55 is formed of a single piece of sheet metal and has a base portion |56 (Fig. 6) which is secured to the underside of the circuit breaker cover 23 b y a pair of rivets |51 (Fig. 3). The bracket has two inwardly extending plates |59 which are slightly spaced from one another. The locking lever |53 extends between the plates |59 of the bracket |55 and is pivoted thereto by a pivot pin I6 the ends of which are riveted over against the plates. A pair of spacing washers |63 (Fig. 3) are disposed on the pivot pin |6| on the opposite sides of the locking lev'er |53 to take up any lateral play in the locking lever |53 and to provide for rotation thereof wit-hout binding against the plates |59.

The locking lever |53 is provided with a projection |65 which is adapted to engage or block movement of the lower edge of the latch member IUI when the locking lever |53 is in locking v position, thereby preventing releasing or tripping movement of this latch member and the trip bar 9| to which it is secured. In the locking position of the locking lever, the projection |65 thereof thus prevents tripping of the circuit breaker either in response to an overload or by any jars or shocks which might otherwise move the trip bar and trip the breaker.

As has previously been pointed out, it is not suilcient merely to lock the latch or tripping means in order to prevent opening of the circuit breaker contacts, because shocks or jars may occur which are so severe as to cause opening of the circuit breaker by jarring the Voperating handle 15 and operating lever 6l"to open position thereby jarring the circuit breaker open in this manner. In order to avoid this, the locking lever |53 is also prowfded with an upwardly projecting extension |61 which is adapted to occupy a blocking position under the lower end of the arcuate portion 19 of the handle 15, as shown in Fig. 1, when the locking lever |53 is in its locking position. In this position, the extension |61 prevents anysubstantial movement of the operating handle 15, the operating lever 6|, and the springs 61 away from their closed position so that jars or shocks cannot cause the breaker to be jarred open by movement of any of these elements. The circuit breaker operating toggle 63-65 is itself locked in the overcenter position by the operating springs '61 and the reactive pressure of the resilient contact arms" 3| so that this toggle cannot be caused to collapse by shocks or jars as long as the operating lever 6| is held in closed or substantially closed position.

The locking lever 53 is biased in a counterclockwise direction as viewed in Fig. 1 about its pivot |6| to a non-locking position'as shown in Fig. 2 by means of a compression spring |69 disposed between the locking lever and the supporting bracket |55. In the non-locking position of the locking lever |53, the projections |65 and |61 thereof are disposed out of the path of move ment ofthe latch member |0| and operating handle 15 ,respectively so that the locking means locking lever |53 whereby the shown in Figs. 5

agasaavo does'not interfere with either tripping or manual operation of the circuit breaker.

The locking lever |53 is adapted to be manually set to locking or non-locking position by means of an operating knob |1| of insulating material which is rotatably mounted on the front of the circuit breaker cover 23 in a position below the operating handle 15. The knob |1| has a shaft |13 secured thereto which extends through the cover 23 and is rotatable in a bearing/or bushing |.15 secured to the mounting bracket |55, the inner reduced end of the bushing being riveted over against the base portion |55 of the bracket |55. The shaft |13 has a non-circular portion |11 which fits tightly in a correspondingly noncircular recesjs vin the knob |1|. The inner end of the shaft |13 has a cam |19 rigidly secured thereon, and the edge of this cam engages a cooperating projection |9| on the lower end of the mentnf the locking lever. prises a generally circular disk which is secured eccentrically to the shaft |13. The sides of the bracket |55 have openings, as shown in Fig. 6, to accommodate the cam |19. of the cam |19 is in contact withv the projection |9| of the locking lever, the biasing spring |59 maintains the locking lever in non-locking position as shown in Fig. 2. However, when the knob cam controls move- I) The cam |19 com- When the low part 1| isl rotated 180 in either direction from the N non-locking position shown in Fig. 2to the locking position shown in Fig. 1, the high portion-of the cam moves the locking lever |53 to locking positioncand maintains it in locking position to lock the circuit breaker cam |19 is provided with a series of notches asand 6 and the projection |9I which engages the cam has a beveled engaging edge so that the cam and lever will be held firmly by the spring |59 in any position to which the lockinge means are manually set. The teeth formed by the notches are rounded to permit manual rotation of the knob and cam. Sincev the projection |9| or the locking lever |53 bears against the cam in a direction radial tothe axis of the shaft |13, shocks or jars will not cause the cam to be rotated away from the position to which it is set. g

A trim plate |82 the circuit breaker cover has a circular'iiange' portion surrounding the base of the knob |1|. This iiange of the trim is marked with the 'words locked and unlocked" and the front of the` knob is provided' with an arrow to cooperate withthe markings to indicate the p'osition of the locking means.

The locking means under normal conditions is is secured to the from side of always set in unioeked position as yshown m Fig.

2. Y In this position, the circuit breaker may be operated manually, or automatically on overload, without interference by the locking lever. If it is desired to lock th-circuit breaker closed, the knob |1I is rotated 180 from the unlocked position shown in Fig. 2 to the locked position shown in Fig.,1. This movement of the knob causes the cam |19 to' move the locking lever to the locking position shown in Fig. 1, thereby locking the circuit breaker closed to prevent opening thereof. In this position, the circuit breaker cannot be tripped open because the latch member |||I is locked inlatching position, nor can the contacts be opened by jarring the handle'or operating member because the projection |61 locks the operating handle against-substantial movement away from 'the closed position.

closed. The edge of the $5 'the locking knob |1| It may sometimes be desired to close the circuit breaker against an overload. This can`be accomplished by first rotating the knob |1| toward locking position as far as it will go, its movement being ylimited .by the projection |61 engaging the under surface of the arcuate handle shield 19. In this position, however, projection |65 is close enough to the latch member |9| to positively prevent unlatching of the releasable lever 1|. The operating handle 15 may now be moved to closed position closing the breaker .even though an overload exists which would ordinarily be suiiicient to trip the breaker. After the handle has been moved to closed position, may be turned .on to its completely locked position, thus completing the locking of the circuit breaker in the closed position. The same result may also be accomplished by moving the operating handle far enough toward closed position to allow movement of the locking lever tol locking position, and 'turning the knob |1| of the locking device to the full locking position. Y

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details thereof and arrangement of parts may be made without departing from some of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given the broadest interpretation permissible in the light of the prior art.

We claim as our invention:

1. A circuit breaker comprising relatively movable contacts, operating mechanism therefor includi'ng an operating member movable to close said contacts, tripping means operable to cause opening of said contacts irrespective of the position of said operating member, and locking means movable to a locking position in which it is effective to prevent tripping of the breaker and in which it is also eilective to prevent opening of said contacts by other than a tripping operation.

2. A circuit breaker comprising relatively movable contacts, operating mechanism therefor inby rivets and' this plate |50 cluding an operating member movable to close said contacts, tripping means including a tripping member movable to cause opening oi said contacts irrespective of the position of said operating member, and locking means movable to a locking position in which it is effective to prevent tripping movement of the trip member and in which it is also eiective to prevent opening of said contacts by other than a trippn operation.

3. A circuit breakercomprising relatively movable contacts, operating mechanism therefor including an operating member movable to close said contacts, tripping means operable to cause opening of said contacts irrespective of the pomember, and locking sition of said operating means movable to a locking position in which it is eiIective to ,prevent trippingv of the breaker and in which it is also effective to prevent opening of the breaker by a part of the mechanism connected to said contacts. l

4. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member lmovable to close said .contactatripping means operable to cause opening of said contacts irrespective of the position of said operating member, and locking ,means-settable to a locking position to lock said.

the position of said circuit breaker closed and prevent opening of the breaker either by said' tripping means or by parts of the mechanismconnected to said contacts.

5. A circuit breaker comprising relatively movable contacts, operating mechanism thereforincluding an operating member movable to close said contacts, tripping means operable to cause opening of said contacts irrespective of the pocluding an operating member movable to open and to close said contacts, tripping means operable to cause opening of said contacts irrespective of the position of said operating member, and locking means settable to a locking position in which it is effective to prevent tripping of the breaker and in which it isv also effective to prevent opening of said contacts by said operaing mechanism.

7. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to close said contacts, tripping means operable to cause opening of said contacts irrespective of the position of said operating member, and locking means settable to a locking position in which it is effective to prevent tripping of the breaker and in which it is also effective to hold said v`operating member in closed position thereby. preventing opening of said contacts.

8. A circuit breaker. comprising relatively movable contacts, operating mechanism therefor including an operating member movable to a closed position to close said contacts, tripping means operable to cause opening of the contacts irrespective of the position of said operating member, and locking means comprising a locking member movable to a locking position in which a portion thereof locks the 4tripping means to prevent tripping of the breaker and another portion thereof locks said operatingmember in closed posticn thereby preventing opening of said contac s.

9. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to a closed position to close said contacts, a member movable from one position to a second position to cause opening of said `contacts irrespective o1' the position of said operating member, said last-mentioned member being biased to said second position at least when said contacts are closed, holding means for holding said member in said one position, electroresponsive means operable to cause said holding means to permit movement of said member `to said second position,"and locklng means movable to a locking position' 4in which a portion thereof prevents movement of said member from said one position and in which another portion thereof prevents opening movement of a part of the mechanism connected to the movable contact.

10. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to close said contacts, a spring biased member releasable to cause opening of said contacts irrespective of operating member, a latch for normally restraining said releasable member, electroresponsive means. operable to cause said latch to release said releasable member, and locking means settable to a locking position in which a portion thereof prevents release of ysaid releasable member and in which another portion thereof prevents opening movement` of al part con-l nected to said movable contact thereby preventing opening of said contacts.

11. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to closed position to close said contacts, a member movable from one position to a second position to cause opening of the contacts irrespective of the position of said operating member. holding means fornormally restraining said member in said one position, electroresponsive means operable to cause said holding means to permit movement ating member, a latch for normally restraining said releasable member, electroresponsive means operable to cause said latch to release said releasable member, and locking means comprising a locking element movable from a non-locking position to a locking position in which a portion thereof prevents release of said releasable member and in which another portion thereof locks said operating member in closed position.

13. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to close said contacts, tripping means operable to cause opening of said contacts irrespective of the position of said operating member, and locking means comprising a locking element movable from a 'non-locking position to a locking positionin which a portion thereof prevents tripping of the breaker and another portion thereof prevents opening of said contacts, and a knob rotatably mounted on the front of the breaker and operable to cause movement of said locking element to locking or non-locking position. 14. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to open and to close said contacts, a spring biased member releasable to cause opening of said contacts irrespective of the position of said operating member, a latch for normally restraining said releasable member, electroresponsive means operable to cause said latch to effect release of said releasable member, and locking means comprising a pivoted locking element movable from a non-locking position to a locking position in which it prevents release of said releasable member, and a knob rotatably mounted on the front of said breaker manually operable to cause movement of said locking element to non-locking or locking position.

15. A circuit breaker comprising relatively including an operating and to close said contacts, a spring biased member releasable to cause opening of said contacts irrespective of the position of said operating member, a latch for normally restraining said releasable member, electroresponsive means operable to cause said latch to release said member, and a locking means comprising a locking element movable from a non-lockingA position to a locking position in which a portion thereon prevents release of said releasable member and in which another portion thereof locks said operating member in closed position. and a knob rotatably mounted on the front of the breaker for moving said locking element to locking or nonlocking position.

16. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to open and to close said contacts, a spring biased member releasable to cause opening of said contacts irrespective of the position of said operating member, a latch for normally restraining said releasable member, electroresponsive means operable to cause said latch to release said member, and a locking means comprising a pivoted locking element movable from a non-locking position to a locking position in which a portion thereon prevents release of said releasable member and in which another portion thereof locks said operating member in closed position, and a knob rotatably mounted on the front of the breaker for moving said locking element to locking or nonlocking position. a

17. A multipole circuit breaker comprising a plurality of movable contact members mechanically connected for movement together, an operating mechanism for actuating said contact members including an operating member movable to operate said contact members to closed circuit position, a member releasable to cause said contact members to be moved to open circuit position irrespective of the position of said operating member, a trip bar having a latch for normally restraining said releasable member, a plurality of electro-responsive tripping means one for at least two of the poles of said breaker'each oper able in response to predetermined abnormal conditions in the circuit of its pole to `cause movement oi' said trip bar and latch to release said releasable member, and locking means movable from a non-locking to a locking position in which it is eiective to prevent release of said releasable memberand also to prevent opening of said contact members by said operating mechanism.

18. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating member movable to close said contacts, tripping means operable 'in response to predetermined conditions to cause opening of said contacts irrespective of the position of said operating member, and locking means movable from a non-locking position to a locking position in which it is effective to prevent trip ping of the breaker and in which it is also effective to prevent opening of said contacts by.

said operating mechanism, said locking means also being settable to prevent tripping of the breaker so as to permit said breaker to be closed against an overload condition.

19. A circuit breaker comprising relatively movable contacts, operating mechanism therefor comprising an operating member movable to open and to close said contacts, a spring biased member releasable to cause opening of said contacts irrespective of the position of said operating member, a latch for normally restraining said releasable member, electroresponsive means operable in response to predetermined overload conditions to cause said latch to release said releasable member, and' locking means comprising a locking element movable from a non-locking position to a locking position in which a portion thereof prevents release of said releasable member and in which another portion thereof locks said' operating member in closed` position, said locking element also being settable to a position in which the nrst mentioned portion thereof prevents release of said releasable member and a1- lows the circuit breaker to be closed and maintained closed against said predetermined overload conditions.

HILLER D. DORFMAN. GERALD J. FREESE. 

